IPAC2011 - Classification: 02 Synchrotron Light Sources and FELs / A16 Energy Recovery Linacs (ERLs)

Paper

Title

Page

The Status of the ALICE Accelerator R&D Facility at STFC Daresbury Laboratory

934

F. Jackson, D. Angal-Kalinin, R. Bate, R.K. Buckley, S.R. Buckley, J.A. Clarke, P.A. Corlett, D.J. Dunning, J.-L. Fernández-Hernando, A.R. Goulden, S.F. Hill, D.J. Holder, S.P. Jamison, J.K. Jones, L.B. Jones, A. Kalinin, S. Leonard, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, A.J. Moss, B.D. Muratori, T.T. Ng, J.F. Orrett, S.M. Pattalwar, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, A.D. Smith, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P. Harrison, G.M. Holder, A.L. Schofield, P. Weightman, R.L. Williams, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
M. Surman
STFC/DL/SRD, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Science and Technology Facilities Council
The ALICE accelerator, the first energy recovery machine in Europe, has recently demonstrated lasing of an infra-red free electron laser (IR-FEL). The current status of the machine and recent developments are described. These include: lasing of the IR-FEL, a programme of powerful coherent terahertz radiation research, electro-optic diagnostic techniques, development of high precision timing and distribution system, implementation of digital low level RF control. ALICE also serves as an injector for the EMMA non-scaling FFAG machine.

Slides TUODA03 [1.648 MB]

TUPO026

Developments towards a Full Energy Recovery Linac

1494

P. vom Stein, J.H. Hottenbacher, A. Metz
RI Research Instruments GmbH, Bergisch Gladbach, Germany

Energy Recovery Linacs (ERLs) are high potential candidates for driving light sources based on laser Compton scattering with high brilliance photon beams and sub pico second time structure. We report on developments for an advanced ERL design, which allows the recovery of nearly full electron beam energy up to the limits set by the energy width of the beam. This “Full” Energy Recovery Linac (FERL) allows a substantial reduction of the complexity of the accelerator systems resulting into a very compact light source design suitable for industrial and medical applications.

TUPO028

Emittance Compensation Scheme for the BERLinPro Injector

1497

A.V. Bondarenko, A.N. Matveenko
HZB, Berlin, Germany

Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam (1 mm•mrad normalized), as required for future ERL-based synchrotron light sources. Given the flexibility ERLs provides, a short bunch operation mode will also be investigated. The space charge is the main reason of emittance degradation in injector due to rather low injection energy (7 MeV). The implementation of emittance compensation scheme in the injector is necessary to achieve such low emittance. Since injector’s optics is axially non-symmetric, the 2D- emittance compensation scheme* is proposed to be used. Other sources of emittance growth are also discussed.
* S.V. Miginsky, "Emittance compensation of elliptical beam", NIM A 603 (2009) 32.

TUPO029

Status of the BERLinPro Optics Design

1500

A.N. Matveenko, M. Abo-Bakr, A.V. Bondarenko, A. Jankowiak, J. Knobloch, B.C. Kuske, Y. Petenev
HZB, Berlin, Germany

Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam (1 mm•mrad normalized), as required for future ERL-based synchrotron light sources. Given the flexibility ERLs provides, a short bunch operation mode will also be investigated. Current optics was designed to allow of low emittance and short bunch operation modes. Optics is flexible to suppress BBU and minimize CSR effects. Estimation of impact of ion accumulation, wake fields, halo and chromatic aberrations is given. Requirements for beam diagnostic system, alignment accuracy and power supply stability are investigated.

TUPO031

The Shielding Design of BERLinPro

1503

K. Ott, M. Helmecke
HZB, Berlin, Germany

Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin.
The Helmholtz-Zentrum Berlin started in January 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro as a demonstrator of ERL science and technology. BERLinPro consists of a SRF photo injector, a merger, superconducting booster and linac modules, the ring and a beamdump. The energy is 50 MeV, the maximum current is 100 mA (cw), acceleration to higher energies is an option for the future. The low energy parts of the machine are operated at about 10 MeV. Due to the potential radiation hazard posed by the tremendous beampower the facility will be placed subterraneously. The shielding concept is presented here. We used the Monte Carlo code FLUKA to calculate the details of the shielding, activations, energy doses for radiation damage and energy spectra for realistic scenarios. Due to computing time reasons we used FLUKA calculations in the 50 MeV to 1 GeV range to derive analytical formulas for the vertical shielding. Extrapolation of existing formulas valid in the GeV range (or below 100 MeV) are not applicable because of the rapidly increasing cross section of photo pion production between 100 and 200 MeV.

TUPO033

Emittance Minimization by Courant-Snyder Parameter Scan in Merger Section at the Compact Energy Recovery Linear Accelerator.

1506

J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea
E.-S. Kim
KNU, Deagu, Republic of Korea
T. Miyajima
KEK, Tsukuba, Japan

The project of compact-Energy Recovery Linac(c-ERL) at Photon Factory in KEK is a test facility for the 5 GeV ERL, which is one of the candidates of next generation light source. It consists of injector system, merger section, main SRF section, return arc, long straight section and beam dump. The injector system produces beams with a low-energy of 5 MeV and low-emittance less than 1 mm-mrad. It causes the large emittance growth by space charge force in merger section, which consists of two rectangular type dipole magnets and one sector type magnet. Dispersion also causes the displacement of bunch sllice on horizontal plane. The displacement of bunch slice is laid on the kick angle induced by space charge force. Also, each slice has the orientation of the phase ellipse on horizontal phase space. Therefore, the emittance growth due to the displacement of bunch sllice induced by space charge force in the horizontal phase space can be minimized by matching the displacement to the orientation of the phase ellipse at the exit of merger. We present the results of the emittance minimization performed by mathcing of the angle of the phase ellipse by scan of CS (Courant-Snyder) parameter.

TUPO034

Longitudinal Stability of ERL with Two Accelerating RF Structures

1509

Ya.V. Getmanov, O.A. Shevchenko
BINP SB RAS, Novosibirsk, Russia
N. Vinokurov
NSU, Novosibirsk, Russia

Modern ERL projects use superconductive accelerating RF structures. Their RF quality is typically very high. Therefore, the RF voltage induced by electron beam is also high. In ERL the RF voltage induced by the accelerating beam is almost canceled by the RF voltage induced by the decelerating beam. But, a small variation of the RF voltage may cause the deviations of the accelerating phases. These deviations then may cause further voltage variation. Thus the system may be unstable. The stability conditions for ERL with one accelerating structure are well known [*, **]. The ERL with split RF structure was discussed recently [***, ****]. The stability conditions for such ERLs are discussed in this paper.
* L. Merminga et al.,Annu. Rev.Nucl. Part. Sci. 53 (2003) 387.
** N.A. Vinokurov et al.,Proc. SPIE 2988 (1997) 221.
*** D. Douglas, ICFA BD-Nl 26 (2001) 40.
****N.A. Vinokurov et al.,Proc. IPAC’10.

TUPO035

Beam Dynamics at the ALICE Accelerator R&D Facility

1512

F. Jackson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Science and Technology Facilities Council
ALICE is an energy recovery accelerator which drives an infrared free electron laser (IR FEL), based at STFC Daresbury Laboratory. Beam dynamics are of primary importance for the operation of the IR FEL, to ensure sufficient peak current with minimal energy spread and transverse emittance. Measurements of beam parameters are presented and compared with particle tracking simulations. Of particular interest in the ALICE machine is the relatively long injection line where space charge and velocity bunching effects can be significant.

WEOAA03

Approach to a Start-to-end Simulation of 2-loop Compact Energy Recovery Linac

1909

M. Shimada, K. Harada, Y. Kobayashi, T. Miyajima, N. Nakamura, S. Sakanaka
KEK, Ibaraki, Japan
R. Hajima
JAEA, Ibaraki-ken, Japan

Transport of an extreme low emittance electron beam is critical issue in an energy recovery linac. In particlar, the space charge effect on an electron bunch in the injector with lower than 5 - 10 MeV induces a large emittance growth. To suppress the emittance growth by such as an optimization of the solenoid magnets, a nonlinear effect should be clarified by a three dimensional tracking simulation. The cons is that it consumes a enormous simulation time. The approach is not suitable for a double loop circulation because the simulation time depends on the transport length. Therefore the beam dynamics and optics are calculated by a start-to-end (S2E) simulation, in which the simulation code is switched after the full acceleration. We used 'general particle tracking (GPT)' for injector electron beam and 'elegant' for a circulator electron beam.

Slides WEOAA03 [3.951 MB]

Paper	Title	Page
TUODA03	The Status of the ALICE Accelerator R&D Facility at STFC Daresbury Laboratory	934
	F. Jackson, D. Angal-Kalinin, R. Bate, R.K. Buckley, S.R. Buckley, J.A. Clarke, P.A. Corlett, D.J. Dunning, J.-L. Fernández-Hernando, A.R. Goulden, S.F. Hill, D.J. Holder, S.P. Jamison, J.K. Jones, L.B. Jones, A. Kalinin, S. Leonard, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, A.J. Moss, B.D. Muratori, T.T. Ng, J.F. Orrett, S.M. Pattalwar, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, A.D. Smith, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P. Harrison, G.M. Holder, A.L. Schofield, P. Weightman, R.L. Williams, A. Wolski The University of Liverpool, Liverpool, United Kingdom M.D. Roper STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom M. Surman STFC/DL/SRD, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Science and Technology Facilities Council The ALICE accelerator, the first energy recovery machine in Europe, has recently demonstrated lasing of an infra-red free electron laser (IR-FEL). The current status of the machine and recent developments are described. These include: lasing of the IR-FEL, a programme of powerful coherent terahertz radiation research, electro-optic diagnostic techniques, development of high precision timing and distribution system, implementation of digital low level RF control. ALICE also serves as an injector for the EMMA non-scaling FFAG machine.
	Slides TUODA03 [1.648 MB]

TUPO026	Developments towards a Full Energy Recovery Linac	1494
	P. vom Stein, J.H. Hottenbacher, A. Metz RI Research Instruments GmbH, Bergisch Gladbach, Germany
	Energy Recovery Linacs (ERLs) are high potential candidates for driving light sources based on laser Compton scattering with high brilliance photon beams and sub pico second time structure. We report on developments for an advanced ERL design, which allows the recovery of nearly full electron beam energy up to the limits set by the energy width of the beam. This “Full” Energy Recovery Linac (FERL) allows a substantial reduction of the complexity of the accelerator systems resulting into a very compact light source design suitable for industrial and medical applications.

TUPO028	Emittance Compensation Scheme for the BERLinPro Injector	1497
	A.V. Bondarenko, A.N. Matveenko HZB, Berlin, Germany
	Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam (1 mm•mrad normalized), as required for future ERL-based synchrotron light sources. Given the flexibility ERLs provides, a short bunch operation mode will also be investigated. The space charge is the main reason of emittance degradation in injector due to rather low injection energy (7 MeV). The implementation of emittance compensation scheme in the injector is necessary to achieve such low emittance. Since injector’s optics is axially non-symmetric, the 2D- emittance compensation scheme* is proposed to be used. Other sources of emittance growth are also discussed. * S.V. Miginsky, "Emittance compensation of elliptical beam", NIM A 603 (2009) 32.

TUPO029	Status of the BERLinPro Optics Design	1500
	A.N. Matveenko, M. Abo-Bakr, A.V. Bondarenko, A. Jankowiak, J. Knobloch, B.C. Kuske, Y. Petenev HZB, Berlin, Germany
	Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam (1 mm•mrad normalized), as required for future ERL-based synchrotron light sources. Given the flexibility ERLs provides, a short bunch operation mode will also be investigated. Current optics was designed to allow of low emittance and short bunch operation modes. Optics is flexible to suppress BBU and minimize CSR effects. Estimation of impact of ion accumulation, wake fields, halo and chromatic aberrations is given. Requirements for beam diagnostic system, alignment accuracy and power supply stability are investigated.

TUPO031	The Shielding Design of BERLinPro	1503
	K. Ott, M. Helmecke HZB, Berlin, Germany
	Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin. The Helmholtz-Zentrum Berlin started in January 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro as a demonstrator of ERL science and technology. BERLinPro consists of a SRF photo injector, a merger, superconducting booster and linac modules, the ring and a beamdump. The energy is 50 MeV, the maximum current is 100 mA (cw), acceleration to higher energies is an option for the future. The low energy parts of the machine are operated at about 10 MeV. Due to the potential radiation hazard posed by the tremendous beampower the facility will be placed subterraneously. The shielding concept is presented here. We used the Monte Carlo code FLUKA to calculate the details of the shielding, activations, energy doses for radiation damage and energy spectra for realistic scenarios. Due to computing time reasons we used FLUKA calculations in the 50 MeV to 1 GeV range to derive analytical formulas for the vertical shielding. Extrapolation of existing formulas valid in the GeV range (or below 100 MeV) are not applicable because of the rapidly increasing cross section of photo pion production between 100 and 200 MeV.

TUPO033	Emittance Minimization by Courant-Snyder Parameter Scan in Merger Section at the Compact Energy Recovery Linear Accelerator.	1506
	J.G. Hwang Kyungpook National University, Daegu, Republic of Korea E.-S. Kim KNU, Deagu, Republic of Korea T. Miyajima KEK, Tsukuba, Japan
	The project of compact-Energy Recovery Linac(c-ERL) at Photon Factory in KEK is a test facility for the 5 GeV ERL, which is one of the candidates of next generation light source. It consists of injector system, merger section, main SRF section, return arc, long straight section and beam dump. The injector system produces beams with a low-energy of 5 MeV and low-emittance less than 1 mm-mrad. It causes the large emittance growth by space charge force in merger section, which consists of two rectangular type dipole magnets and one sector type magnet. Dispersion also causes the displacement of bunch sllice on horizontal plane. The displacement of bunch slice is laid on the kick angle induced by space charge force. Also, each slice has the orientation of the phase ellipse on horizontal phase space. Therefore, the emittance growth due to the displacement of bunch sllice induced by space charge force in the horizontal phase space can be minimized by matching the displacement to the orientation of the phase ellipse at the exit of merger. We present the results of the emittance minimization performed by mathcing of the angle of the phase ellipse by scan of CS (Courant-Snyder) parameter.

TUPO034	Longitudinal Stability of ERL with Two Accelerating RF Structures	1509
	Ya.V. Getmanov, O.A. Shevchenko BINP SB RAS, Novosibirsk, Russia N. Vinokurov NSU, Novosibirsk, Russia
	Modern ERL projects use superconductive accelerating RF structures. Their RF quality is typically very high. Therefore, the RF voltage induced by electron beam is also high. In ERL the RF voltage induced by the accelerating beam is almost canceled by the RF voltage induced by the decelerating beam. But, a small variation of the RF voltage may cause the deviations of the accelerating phases. These deviations then may cause further voltage variation. Thus the system may be unstable. The stability conditions for ERL with one accelerating structure are well known [, ]. The ERL with split RF structure was discussed recently [, *]. The stability conditions for such ERLs are discussed in this paper. L. Merminga et al.,Annu. Rev.Nucl. Part. Sci. 53 (2003) 387. N.A. Vinokurov et al.,Proc. SPIE 2988 (1997) 221. * D. Douglas, ICFA BD-Nl 26 (2001) 40. ****N.A. Vinokurov et al.,Proc. IPAC’10.

TUPO035	Beam Dynamics at the ALICE Accelerator R&D Facility	1512
	F. Jackson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Science and Technology Facilities Council ALICE is an energy recovery accelerator which drives an infrared free electron laser (IR FEL), based at STFC Daresbury Laboratory. Beam dynamics are of primary importance for the operation of the IR FEL, to ensure sufficient peak current with minimal energy spread and transverse emittance. Measurements of beam parameters are presented and compared with particle tracking simulations. Of particular interest in the ALICE machine is the relatively long injection line where space charge and velocity bunching effects can be significant.

WEOAA03	Approach to a Start-to-end Simulation of 2-loop Compact Energy Recovery Linac	1909
	M. Shimada, K. Harada, Y. Kobayashi, T. Miyajima, N. Nakamura, S. Sakanaka KEK, Ibaraki, Japan R. Hajima JAEA, Ibaraki-ken, Japan
	Transport of an extreme low emittance electron beam is critical issue in an energy recovery linac. In particlar, the space charge effect on an electron bunch in the injector with lower than 5 - 10 MeV induces a large emittance growth. To suppress the emittance growth by such as an optimization of the solenoid magnets, a nonlinear effect should be clarified by a three dimensional tracking simulation. The cons is that it consumes a enormous simulation time. The approach is not suitable for a double loop circulation because the simulation time depends on the transport length. Therefore the beam dynamics and optics are calculated by a start-to-end (S2E) simulation, in which the simulation code is switched after the full acceleration. We used 'general particle tracking (GPT)' for injector electron beam and 'elegant' for a circulator electron beam.
	Slides WEOAA03 [3.951 MB]